Down Syndrome is a variety of congenital moderate-to-severe mental retardation that occurs due to the presence of extra chromosome material on chromosome number 21. Additional clinical features include microcephaly, short stature, congenital heart disease, duodenal atresia, epicanthal folds, flat nose, and sloping forehead. There is increased susceptibility to infection and acute leukemia, and an advanced aging process, usually leading to dementia in the 4th or 5th decade that results in a decreased life expectancy